摘要 |
A hydraulic actuator with reduced interior volume includes a locking mechanism engageable with the main ram of the actuator to hold it in a fully retracted position without backlash. The locking mechanism comprises three locking jaws that move synchronously in a radial direction between lock or unlock position. Each of the jaws engage a groove cut into a rod adjacent the piston head of the main ram; the jaws are cammed into a locking position by a conical sleeve actuated by hydraulic pressure under the control of the main control valve. Jaw deactivation is accomplished by an opposed pressure which disengages the conical sleeve and the jaws are then spring biased into a cammed open position as the main ram begins to extend. Springs located between the individual jaw segments assist the camming action for opening the jaws.
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